This invention relates generally to coupler assemblies for railway cars and the like, and, more specifically, to an improved coupler for such a coupler assembly. Although the invention will be described with particular reference to a coupler for an F-type rotary coupler assembly, it will be appreciated that certain features thereof may also be used or adapted to use in other coupler assembly applications.
After the introduction of the rotary coupler assembly, a train comprised of loaded railways cars of the open top or hopper-type (which may contain coil, ore etc.) could be emptied without having to uncouple and separate the cars. This was accomplished by rotating each car up to 180.degree. about its longitudinal centerline while the car remained connected on both ends to adjacent cars. This capability speeded up the gravity unloading process. Rotary coupling systems typically include a yoke assembly and a coupler, along with a follower, a draft gear, and a striker. In addition, the yoke assembly may include a cylindrical connector, a connecting pin, and pin support apparatus.
Couplers of the known type include a coupler head, an elongated shank, and a butt portion terminating in a free end. The coupler shanks in prior non-rotary railway coupler assemblies have been of a large, generally square cross-section, whereas coupler shanks in prior rotary coupler assemblies have generally been circular and of smaller cross-section than the shanks of non-rotary types. The tremendous growth in size of railroad cars over the past decade has, however, placed severe strains on the conventional couplers used in those coupling systems presently available.
Moreover, disrepair of railroad beds has caused misalignment of trackways which produces undesirable movement between adjacent railroad cars. Such movement, along with wear caused by rapid mileage accumulations, creates heretofore unknown fatigue failures in the components of conventional car coupling assemblies. One of the components which fails is the coupler. Thus, it has been considered desirable to provide a coupler which is stronger and more durable even under the most severe service conditions.
In order to enhance the strength of one type of coupler assembly, the components thereof have been redesigned. Such redesign is disclosed in the commonly assigned U.S. patent applications to Richard M. Hanula, Ser. No. 322,217, now U.S. Pat. No. 4,428,489, entitled AN IMPROVED ROTARY RAILROAD CAR COUPLER, and Ser. No. 518,822 filed 8-1-83, now abandoned, entitled STRIKER FOR RAILWAY CARS, the teachings of which are incorporated hereinto by reference.
Another coupler assembly component which has been improved is the yoke. Such improvement is disclosed in the commonly assigned U.S. patent application to Richard M. Hanula which is being filed concurrently herewith, entitled IMPROVED YOKE FOR RAILWAY CAR COUPLER ASSEMBLY, Ser. No. 720,690, filed on Apr. 8, 1985, the teachings of which are also incorporated hereinto by reference. The improved yoke disclosed therein has been redesigned to better withstand stresses. To accommodate such redesign, it has also been necessary to enlarge the yoke aperture to properly accept the reinforced coupler shank of the present invention.
With regard to conventional F-type coupler shanks, it has been found that heavy wear and scoring occurs on the coupler butt end due to the presence of concentrated loads on the corner areas, and too little initial load bearing area between conventional contact faces of the coupler and follower. This result is caused by the fact that a convex contact face on the coupler butt portion is likely to have a larger radius through tolerance variations that a concave contact face on an associated follower. This, in turn, means that the coupler butt portion will rest on its corners due to its generally rectangular shape.
The reason for providing both the butt portion and follower contact faces with substantially the same radius is to provide the center of the coupler butt portion with some relief for avoiding adverse loading at that area. Such loading would quickly lead to a fracture of the coupler butt portion at its center. Since this type of relief brings about the above noted difficulty with contact at the outer four corners of the coupler butt portion, it would be desirable to provide means for insuring better initial contact between the spherical contact faces of the coupler and follower.
The present invention contemplates a new and improved railway car coupler which overcomes the foregoing difficulties and others, and which provides better and more advantageous overall results.